ML20094P172

Natl Inst of Stds & Technology Reactor Operations Rept, 1991

ML20094P172
Person / Time
Site:	National Bureau of Standards Reactor
Issue date:	12/31/1991
From:	Rowe J NATIONAL INSTITUTE OF STANDARDS & TECHNOLOGY (FORMERL
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9204070263
Download: ML20094P172 (11)

Text

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UNITED GTATEC OUPARTMENT OF COMMERCE National institute of Otznder ds and Technology

\( f ca.oentonrawyano20099 I (301) 975-6210  :)

FTS 879-6210 i FAX (301) 921-9847 March 30, 1992 U.S. Nuclear-Regulatory Commission -

Document Control Desk Washington, DC 20555 Docket #50-184

Subject:

'3en tlemen .

-Transmitted herewith is Operations Report No.44 for the NBSR. The report covers the period January 1, 1991 to December 31, 1991.

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-J Michael Rowe

'hief, Feactor Radiation Division l

Enclosure l

cc: Project Scietist U.S. Nuclear Regulatory Ccmmission Region 1 l 475-Allendale Road

l. King.of Prussia, PA 19406 I

l- Project Manager Non-Power Reactor Directorate U.S. Nuclear Regulatory Commission Washington, DC 20555 l

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Y I. 9204070263 911231 I l

PDR ADOCK 05000184 ('

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N ATIONAL INSTITllTE OF STANDARDS AND TECHNOLOGY REACTOR

, (NBSR)

Docket #50-184 Facility License No. TR 5 Op. rations Report

..#4 4..

January 1,195'1 - December 31,1991 This report contains a summary of activities connected with the operations of the NBSR. It is submitteo in fulfillment of section 7.8(3) of the NBSR Technical Specifica-tions and covers the period l rom January 1,1991 to December 31,1991.

Sectica numbers in the report (such as 7.8(3)(a)) correspo,1d to those used in the Technical Specifications.

l March 30,1992 y ' s pss L--

J ichael Rowe Chief, Reactor Radiation Division

a Page 1 TABLE OF CONTENTS 7.8(3)(a) Summary of Plant Operations v.8(3)(b) Unscheduled Shutdowns 7.8(3)(c) Tabulation of Macr items of Plant Maintenance 7.8(3)(d) Tabulation of Major Changes in the Facility and Procedures, and th : Test a.1d Experiments, Carried Out Without Prior Approval by the NRC Pursuant to 10 CFR 50.59 7.8(3)(e) Summary of Radioactive Material Released and Results of Environmental Surveys Performed 7.8(3)(f) Summary of Significant Exposures Received by Facility Personnel and Visitors i

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19 910perations Report for NBSR (TR-5)

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4 Page 2 7.8(3)(a) Summary of Plant Operations During the calendar year 1991, tne reactor was critical for 5741 hours0.0664 days <br />1.595 hours <br />0.00949 weeks <br />0.00218 months <br /> and the energy generated was 91983 MWH.

In April,1991, one of the main heat exchangers was taken out of service. Reactor operations continued with the remaining heat exchanger at reduced power of 15 MW.

Highlights of this and other significant activities are presented below:

1. Heat Exchangers: A very small leak in the older main heat exchanger proved virtually impossible to find. Repeated efforts and the plugging of numerous tubes were unsuccessful because of the tiny size of the leak, at times less than a drop a minute. The decision was then made to take this heat exchanger out of service and continue operation with the remaining heat exchanger at reduced power of 15 MW.

Fabrication of three new plate-type heat exchangers began in late 1991 with completion expected by the end of 1992.

2. Regulatina Rod Drive: The regulating rod drive had several blown fuses over a period

- of time. The problem was traced to corrosion in some of the pins in the connector, which were repaired.

3. Diesel Batteries: All the batteries for the diesels were replaced with fresh batteriet after several battery failures during diesel stad testing. In the interim, the starting function was tested weekly as required.

4. Drocoed Element: Duiing refueling, a new unirradiated fuel element fell off the tool while being transferred into position in the core, a distance of about one foot. The element was retrieved, was undamaged, inspected and reinserted into its position in the core.

5. Shearing of a Rabbit: During removal _of a rabbit from the sonder-receiver unit ins = a laboratory hood, the operaar noted that the rabbit did not drop out as it should have. He repeated the procedure by cycling the cylinder of the unit to its original position and then back to the drop-out position. 'Apparently, the rabbit had partially dropped initially, which could not be seen by the operator. By cycling the cylinder again, the rabbit and the sample inside it were sheared in half. There was local contamination from the sample which was

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19 91 Operations Report for NBSR (TR-5) rDocket #50-184)

Page 3 cleaned up. One operator was assigned 515 mrem to the hands. There was little or no other

> exposure to personnel.

4

6. Neutron Beam Tube Exoeriment: An experimenter reported that his elbow and forearm might have inadvertently been in a beam for a few minutes while observing adjustments being made to a sample. This could not be confirmed by the senior experimenter making the adjustment and it seems doubtful that the beam was actua!!y open. Nevertheless, the conditions were reconstructed and careful measurements were made. Based on the 4

measurements, it is possible, though not likely, that the individual could have received an exposure of as much as 550 mrem to the elbow as an upper limit. This value was assigned to the individuars exposure record. In the meantime, all experimenters and researchers -

were reminded and instructed that all changes must be performed with the beam turned off, in addition, the articulated bars that mark the beam position were made rigid so that they cannot be tilted upwards and streamers were hurig from them.

7. N9JJ1ron Guide Tube: One of the side panels in one of the neutron guide tubes failed.

Most of the glass was subsequently found on the floor underneath the point of failure, but approximately 10% traveled the length of the. tube through a thin magnesium alloy window and was stopped by a 0.060 inch wall aluminum filter cryostat. The failure of a glass panel has no effect on the reactor nor does it present any hazard to personnel. It is suspected that a defect in the glass caused the failure since failure due to radiation damage is considered unlikely. Calculations and comparison with similar facilities showed that the thmshold of radiation damage, sufficient to cause a failure, would not occur for at least anotner 3 years.

The glass was replaced and as a precaution, the first five meters of the guides within the confinement building were tilled with helium. The latter had been planned to be done within six months.

7.8(3)(b)' Unsci aduled Shutdowns

l. There were four (4) scrams due to a commercial power dip during electrical storms. The reactor returned to power immediately.

2. There was one (1) scram due to a commercial power dip. The reactor returned to power immediately.

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l 1 19 91 Operatior:s Report for NBS A (TR-5)

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l Page 4

3. There were two (2) scrams due to a commercial power dips. The reactor stayed shutdown because it was at the end of the fuel cycle.

4. There was a scram due to no apparent cause. After completing the O.l.1.18 check list i

the reactor retumed to power. About ten minutes later the reactor scrammed again and a momentary Hi Flux annunciator was observed. Checked power channels NC-6,7, &

B and found setpoints below 100% Reset the setpoints to 125% and returned to power while monitoring closely

5. There was a scram on low flow when the motor on the #1 main cooling pump shorted out. The reactor returned to power the next day after the motor was replaced.

6. There were three (3) screms due to a commercial power dip because of power company problems. The reacter returned to power immediately two times but on the third attempt the Reg. Rod stopped driving. The reactor was shutdown and a fuse in the Reg. Rod drive motor was replaced. After testing the IN and OUT drive times the reactor was returned to power.

7.8(3)(c) Tabulation of Major items of Plant Maintenance I I i

1. Replaced relief valve at air reducing station #7 (by CO2 gas holder in Process Room)

2. Pluggea two leaking tubes of experimental demin HX i

3. Plugged 6 suspected leaking tubes of HE-1 A: (C/R) 16/6,38/2,39/3,29/9,29/11, &

l 29/41

4. Installed new motor bearings in #1, #4, #5, & #6 secondaiy pumps

5. Changed filters of experimental demin, storage pool, thermal shield, and primary purification systems

6. Cleaned inlet distribution-tree fingers and screens of storage poolIX column

7. Replaced differential pressure switch on DWV-3 (#1 main D2O pump discharge valve)

8. Tightened valve packing of FTV--3

9. Changed both battery banks of A & B diesel generators

10. Changed resin in both thermal shield IX columns

11. Replace 0 motor of #1 main D2 0 pump

12. Replaced sightglasses on diesel fuel day-tank and demin water day-tank

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19 91 Operations Report for NBSR (TR-5)

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Page 5

13. Repaired BT-1 shu 3r assembly

14. Electrical shop performed annual PM's on A & B substations

15. Re;;; aced DWV 403 & 404 with new valves (primary system sample recirc station)

16. Replaced #3 shim arm drive cavity shielding with 2-inch poly sheets instead of using numbered lead bricks

17. Installed new motor for RM 3-1 (secondary N-16 pump #2) 14 Installed new pump on secoridary N-16 pump #1

19. Regenerated demineralized water station IX resin

20. Removed piping that was used to supply steam to cooling tower basin

21. Drained and cleaned cooling tower basin

22. Installed new flow meter for cooling tower make-up

23. Refurbished #2 shim arm drive mechanism

24. Treated numerous thermal shield ring header and floor header leaking cooling ccils to stop/ minimize leakage

25. Installed new seat in SCV-216 (secondary outlet of HE-1 A)

26. Changed air operator diaphragm for DWV-8 (#1 D 2O shutdown pump discharge)

27. Changed air operator diaphragm for DWV-6 (#4 main D 2O pump discharge valve)

28. Changed diaphragm of DWV-133 ( 2-in. drain header in Process Room)

29. Changed out C-4 and C-6 refueling pickup tools

30. Replaced end of small refueling tool

31. Replaced shaft sleeve, mechanical seal. and both impeller gaskets of #2 and #3 main D2O pumps g

32. Removed and cleaned rabbit tip flow indicator for RT-1

33. Removed auto flipping RT-4 rabbit receivor and replaced with old style manual receiver

34. Repaired #2 helium blower sightglass paci..ng leak

35. Replaced diaphragm and solenoid of HEV-4 (helium valve for blowing D 2O to storage tank during refueling)

36. Replaced mechanical seal of #1 experimental demin pump

37. Derformed regularly scheduled Tech Specs and plant PM's

38. Replaced zener diode in annunciator panel AN-3

39. Replaced differential pressure switch on DWV-3 valve

40. Replaced and calibrated millivolt / current transducer on TIA-8

41. Calibrated Secondary Auxiliary Cooling flow FIA-17

42. Replaced GM-tube and calibrated Area Monitor PM1-8

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19 91 Operations Report for NBSH (TR-5)  !

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l 43. Cleaned and wiped setpoint potentiometers on NC-6,7, & 8

44. Renlaced GM-tube and calibrated filter monitor RM 1-13 45, Resoldered connection to #2 Shim Arm Readout l.

46. Replaced flow transmitter on Secondary inlet flow for HE-1B l

47. Replaced meter driver card on RM4-2 l 48. Rep! aced meter alarm assernbly on RM 3-4 & 5

49. Replaced flow transmittM on D20 flow for HE-2 l 50. Replaced level transmitter on Liquid Was% Hold-Up tank

51. Replaced fuse in "A" Regulating Rod motor circuit 1

52. Replaced detector for Radiation Monitor in C-001 lab

53. Replaced card in Primary IX Outlet conductivity monitor

!' 54. Replaced reduction gear in Regulating Rod drive R

55. Replaced zener diode on annunciator pane! AN-5

56. Replaced zener diode on annunciator panel AN-4

57. Repaired Irradiated Air Monitor RMS-4 )

58. Replaced fuse in "A" Regulating Rod motor circuit  ;

59. Cleaned control switch on #1 Shim Arm

60. Replaced "A" Regulating Rod with "B" Regulating Rod 1

61. Replaced annunciator power switch on 125-V DC DCP-2 panel

62. The .following instrument calibration surveillance tests were performed:

N C-1 Nuclear Source Range Start Up NC-2 Nuclear Source Range Start Up TIA-40B Reactor Delta Temperature TRA-2 Reactor Outlet Temperature l FR-1 Reac+or Outlet Flow TR-1 Reactor Delta Temperature LIA-3 Storage tank level calibration

! BTUR Reactor Thermal Power u - NC-7 Nuclear Power Range NC-8 Nuclear Power Range i

FIA-15 Thermal Shield Flow RM 3-4 Irradiated Air Monitor BT-4A&B BT-4 Area Monitor l RM 1-1-10 Reactor '3ui! ding Area Monitors

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1991 Operations Report for NBSR (TR-5)

[ Docket #50-184) i

Page 7 j NC-4 Nurfsar Intermediate o ower Range RM 4-1 Stack Monitor RM 4-2 Auxiliary Stack Monitor FRC-4 Reactor Outer Plenium Flow FRC-3 Reactor Inner Plenium Flow RM 4-4N Criticality Monitor RM 4-4S Criticality Monitor NC-5A Linear Power Range and Regulating Rod Controller LRC-i Reactor Vessel Level NC-3 Reactor Intermediate Power Range PC-3 Normal Air Exhaust Pressure Controller PC-27 Process Room Air Exhaust Pressure Controller S PC-150 - Emergency Fan Controller SPS-151 Vacuum Breaker Controller SPS-150 Emergency Standby Fan Controller NC-9 Nuclear Safety System NC-6 Nuclear Power Range FIA-40 Reactor Flow LIA-40 Reactor Vessel Level TIA-40A Reactor Delta Temperature RM 3-2 Fission Product Monitor RM 3-1 Secondary Cooling N-16 Monitor RM 3-3 Secondary Cooling N-16 Monitor 7.8(3)(d) Tabulation of Major Changes in the Facility and Procedures, and the Test and Experiments, Carried Out Without Prior Approval by the NRC pursuant to 10 CFR 50.59.

Relevant Engineering Changes are summarized below:

ECN-362 Replaced Confinement Building personnel doors with heavy duty automatic opening and closing doors. All functions and alarms are unchanged, therefore there are no unreviewed safety questions.

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1991 Operations Report for NBSR (TR-5)

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i E,CN-370 Installed a level float switch in the Storage Pool pump pit to prevent the water in the pit from overflowing onto the floor by shutting off the make-up water valve to the pit.

This change involves no unreviewed safety question.

ECN-373 Replaced the Amperex #18509 GM tube with a #18529 GM tube in the Helium Sweep monitor system to increase the rang' of detection. This change involves only a change of the detector and does not affect the accident analyses or safety margins and therefore there are no unreviewed safety questions.

ECN-375 installed a bulk storage tank for the helium supply to the D2O sweep gas

~

system. This provides a more dependabie supply of high purity helium without the recessity handling high pressure cylinders. Since this system only provides an additional supply of helium it will not reduce the margin of safety that has been previously evaluated. Therefore there are no unreviewed safety questions.

ECN-378 Installed electric motor soft-starts on the Thermal Shield cooling system pump motors to reduce starting current and torque during power up and thereby reducing the water pressure surges into the thermal shield system. All trips and alarm settings remain the same, therefore there are no unreviewed safet; questions.

ECN-380 Installed an area radiation monitor in room C-001 (known as the Rabbit Lab) to provide indication of a High Radiation level >;ondition created by a rabbit returned to the hood in that room. This enhances the radiation safety of the area and does not impact on reactor systems or reactor safety, therefore there are no unreviewed safety questions.

ECN-383 Installed a new plate-type heat exchanger in the Secondary System to cool and isolate the oil cooling system of the new cryogenic helium compressor. Safety analysis within the body of the ECN shows that this modification does not add to any reactor accident or introduce new ones, nor will it reduce any safety margin. Therefore there are no unreviewed safety questions.

ECN-385 Removed remote readouts for liquid waste system batching tanks which are no longer a part of the liquid waste system. No reactor systems are affected by this channe and therefore does not involve an unreviewed safety question.

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19 91 Operations Report for NBSR (TR-5) ]

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• Page 9 7.8(3)(e) Summary of Radioactive Material Released and Results of Environmental Surveys Performed.

The gaseous waste released was 251 curies of tritium and 971 curies of Argon-41.

There were 1.8 curies of tritium and 1.6 millicuries of other beta-gamma emitters released into the sanitary sewer. Environmental samples of the streams, vegetation, and/or soil, and air showed no significant changes.

7.8(3)(f) Summary of Significant Exposures Received by Facility Perscc net and Visitors.

1. None to visitors.

2. Dosimetry results for this reporting period indicated that no facility personnel received significant exposures.

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19 91 Operations Report for NBSR (TR-5)

[ Docket #50-184]

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